Bispecific Monoclonal Antibodies in Diffuse Large B-Cell Lymphoma: Dawn of a New Era in Targeted Therapy

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma (NHL) worldwide. Currently, approximately sixty percent of patients are cured with R-CHOP as frontline treatment, while the remaining patients experience primary refractory or relapsed (R/R) disease. Recently, the introduction of Pola-R-CHP as front-line therapy has represented a major advance in the management of DLBCL, resulting in improved outcomes. Prognosis of R/R DLBCL patients is poor, particularly for those eligible neither for chimeric antigen receptor (CAR) T-cell therapy nor autologous stem cell transplantation (ASCT), representing a significant unmet clinical need. The advent of bispecific monoclonal antibodies (BsAbs), such as bispecific T-cell engagers (BiTEs), dual affinity retargeting (DART) molecules and IgG-like bispecific antibodies, offers a novel promising therapeutic approach in the treatment of DLBCL, both as frontline treatment and in the R/R setting. BsAbs simultaneously engage two different antigens, a tumor-associated antigen and an immune cell antigen, redirecting T-cells against malignant cells and enhancing the immune response. Most BsAbs developed for the treatment of NHLs engage T-cells via CD3 and malignant B-cells via CD20, a surface antigen expressed on most lymphomatous cells. Engagement of malignant B-cells by BsAbs activates T-cells, leading to the release of multiple cytokines and potentially to two characteristic adverse events: cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The most extensively studied BsAbs, in both the frontline and relapsed/refractory (R/R) settings, include epcoritamab, glofitamab, mosunetuzumab, and odronextamab. Epcoritamab and glofitamab have received FDA and EMA approval for R/R DLBCL after two or more systemic line of therapies. EMA has also approved glofitamab in combination with gemcitabine and oxaliplatin (GemOx) for patients with R/R DLBCL ineligible for ASCT, whereas this indication has not been approved by FDA. Odronextamab is approved by EMA for R/R DLBCL and FL in patients who have received at least two prior lines of therapy, but it has not been approved by FDA. Mosunetuzumab is approved by both agencies-but only for R/R follicular lymphoma (FL). BsAbs represent a breakthrough therapy in the treatment of DLBCL, especially in R/R diseases. The purpose of this article is to review the landscape of BsAbs in DLBCL.